1920-0.

## SERIES 1900 | COMPACT LOW DIFFERENTIAL PRESSURE SWITCHES 

## FEATURES/BENEFITS 

- Compact size and repeatability provides a high-value switch for many industrial and OEM applications 

- Wide range of models from 0.07 in w.c. to 20 in w.c. can meet exacting OEM specifications for a low pressure switch 

- Range screw protected inside enclosure simplifies adjustments and prevents tampering 

## APPLICATIONS 

- Air conditioning refrigeration coil icing detection; defrost cycle initiation 

- Clogged filter detection 

- Variable air volume controller 

## DESCRIPTION 

Our most popular SERIES 1900 combines advanced design and precision construction to make these switches able to perform many of the tasks of larger, costlier units. Designed for air conditioning service, they also serve many fluidics, refrigeration, oven and dryer applications. Series 1900 switches have set points from 0.07 to 20 in w.c. (1.8 to 508 mm). Set point adjustment is easy with range screw located inside conduit enclosure. Internal location helps prevent tampering. UL, CE and CSA listed, and FM approves. For use with air or compatible gases. 

## SPECIFICATIONS 

|SPECIFICATIONS||
|---|---|
|Service|Air and non-combustible,compatiblegases.|
|Wetted Materials|Consult factory.|
|Temperature Limits|-30 to 180°F(-34 to 82.2°C).|
|Pressure Limits|45 in w.c.(11.2 kPa)continuous,10psig (68.95 kPa)surge.|
|Switch Type|Single-pole double-throw(SPDT).|
|Repeatability|±3%.|
|Electrical Rating|15 A @ 120-480 VAC, 60 Hz. Resistive 1/8 HP @ 125 VAC, 1/4 HP @ 250 VAC, 60 Hz. Derate to 10 A for operation at<br>high cycle rates.|
|Electrical Connections|3 screw type,common,normallyopen and normallyclose.|
|Process Connections|1/8″ female NPT.|
|MountingOrientation|Diaphragm in verticalposition. Consult factoryfor otherposition orientations.|
|Set Point Adjustment|Screw type inside conduit enclosure.|
|Weight|1 lb 4.5 oz(581g).|
|AgencyApprovals|CE,CSA,FM,and UL. Optional -EXPL explosion-proof enclosure does notpossess anyagencyapprovals.|



## DWYER INSTRUMENTS, INC. 

T: 219-879-8000 | F: 219-872-9057 | info@dwyermail.com 800-872-9141 

dwyer-inst.com 

## DIMENSIONS 

## WIRING DIAGRAM 

## HOW TO ORDER 

Use the bold characters from the chart below to construct a product code 

SERIES 1900 - Use with non-UL options 1910 - With conduit 1911 - Without conduit 1920 - With conduit; with HP back port 1921  - Without conduit; with HP back port RANGE 00 - 0.07 to 0.15 in w.c. 0 - 0.15 to 0.55 in w.c. 1 - 0.4 to 1.6 in w.c. 5 - 1.4 to 5.5 in w.c. 10 - 3.0 to 11.0 in w.c. 20 - 4.0 to 20.0 in w.c. 

1900 -1 -AT OPTIONS AT - Aluminum tag B - Buna-N diaphragm & O-rings BGAP - B-Gap micro switch DPK - Duct pressure kit EXPL - Cast iron explosion-proof housing G - Gold contact switch LC - Less conduit (1900 units only) MIL - Mil switch MR - Manual reset P - L-bracket mounting PRESET - Preset ST - Stainless steel tag TC - Tropicalization coating V - Vent option VIT - Fluoroelastomer diaphragm & O-rings WP - Weatherproof housing 

## ACCESSORIES 

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|||
|---|---|
|Model|Description|
|A-399|Duct pressure monitor kit; for use with standard or manual reset model switches; includes mounting flange, tubing and adapters|
|A-329|Street ell; brass adapter for applications requiring right angle connections; two required for differential pressures|
|A-302F-A|303 SS static pressure tip with mounting flange; for 3/16" ID rubber or plastic tubing; 4" insertion depth; includes mounting screws|
|A-489|4" straight static pressure tip with flange|

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Important Notice: Dwyer Instruments, Inc. reserves the right to make changes to or discontinue any product or service identified in this publication without notice. Dwyer advises its customers to obtain the latest version of the relevant information to verify, before placing any orders, that the information being relied upon is current. 

## DWYER INSTRUMENTS, INC. 

T: 219-879-8000 | F: 219-872-9057 | info@dwyermail.com 800-872-9141 

dwyer-inst.com 

DS-1900 | 7/17